1. Field of the Disclosure
The present invention generally relates to transitional alumina particulate material and processes for forming same. More specifically, the present invention relates to transitional alumina particulate material having novel morphological features.
2. Description of the Related Art
Aluminous materials have been used in quite a large and varying scope of industrial applications and technologies, from single crystal applications focusing on optical and optoelectronic applications, to polycrystalline abrasive grains used in free abrasives, bonded abrasives, and coated abrasives, for example. Aluminous materials are generally polymorphic, and may include various hydrated forms such as boehmite and gibbsite. Among the various alumina materials, alumina, or aluminum oxide, is a particular material of interest. In various industrial applications, alumina is employed in its hardest and most stable allotropic state, alpha-alumina. However, the transitional forms of alumina, which include gamma, delta, and theta have gained commercial interest as these phases have desirable properties, such as desirable hardness and surface area characteristics that make transitional alumina of great interest in areas as diverse as printing inks and catalyst carriers.
Currently available transitional aluminas are typically processed by heat treating transitional alumina precursor materials such as gibbsite, boehmite, or bayerite to the desired phase transformation temperature. Other techniques rely on direct synthesis via a wet chemical processing, such as through hydrolysis of aluminum alkoxide. Current techniques often suffer from poor yield, high expense, and/or limited flexibility to form new morphologies that may be of interest in emerging markets based on exploitation of transitional aluminas.
Accordingly, as should be clear, a need exists in the art for transitional aluminas that have novel morphological features. In addition to the interest in creating new materials, processing technology enabling the formation of such materials needs to be developed as well. In this regard, such processing technology is desirably cost effective, is relatively straightforward to control, and provides high yields.